Correct "Manage Password" link in Quickling in Diffusion

Summary: Fixes T12080. This was missing a "/", but stop hard-coding these URIs.

Test Plan: Clicked both links with Quickling as a logged-in and logged-out user, ended up in the right place.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12080

Differential Revision: https://secure.phabricator.com/D17151